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O2 Sensor Simulator...

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Anyone know how to make an oxygen sensor simulator? My ZJ is with out a catalytic converter, and I need to duplicate the slower, downstream sine wave you would after the cat has burned off the junk...


Posted that here because an O2 sim is something everyone should know how to do... Myself included. :D


Something tells me Mr. Hornbrod will know how... This electrical stuff is his forte. ;)

Rob L.

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There was a recall on ZJ's (my 96' was covered by it, I'm pretty sure 98's too),

because the code was never put in the ECM to notice the signal from the rear o2 sensor, and tattle when the converter went bad.


Our 96's converter failed at ~85k miles (rattle rattle rattle), with no check engine light.

So we brought it in for the recall, they flashed the new code on the ECM, and handed me a Cat.


I didn't have them install it because they wanted $300+ to also swap the headpipe (which was absolutely perfect), and the muffler/tailpipe (which was junk).



I'm only posting all of this, because it's possible that your ECU isn't even monitoring the rear o2 on your ZJ. :dunno:

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I know you were looking for an electrical fix but I know that some people have been able to get away with a mechanical fix. The cheapest and easiest version was to use two spark plug anti-foulers to move the sensor out of the airstream. You take the first anti fouler and screw it into the exhaust where the O2 sensor would go. Then take the second anti fouler and drill it out so that the O2 sensor can screw into it. If you don't drill it out the O2 sensor will be too long to fit. Once it's drilled out you screw it into the first anti fouler and then screw the O2 sensor into second anti fouler. As long as you have enough clearance to fit the anti foulers (and some exhaust setups don't) and enough slack in the O2 sensor wiring this seems to work pretty well.

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